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Abstract: We determined the short‐ and medium‐term effects of prescribed burns on soil organic matter content and biological activity in grazing areas invaded by the shrub Echinospartum horridum (Vahl) Rothm. in the Pyrenees of Huesca (Spain). Soil samples were collected at 0–1, 1–2, and 2–3 cm depths in triplicate just before the burn, immediately after the burn (T0), and 1 and 5 years later (T1 and T5). We analysed the contents of total soil organic C and N, soil respiration, microbial biomass C, and β‐ d‐glucosidase and acid phosphatase activities. Fire provoked an immediate high decrease in the contents of soil organic C (−40.2%) and N (−26.3%) in the first 3 cm, which were even lower at T5 (−50.3% and −46.5%, respectively). This can be explained as follows: (a) low incorporation of burned organic matter due to removal by wind and run‐off; (b) changes in microclimate increasing soil temperature and enhancing mineralization; and (c) a stimulating effect on decomposition due to the release of nutrients. Soil biological activity was affected at T0 in the first 3 cm (−49.3% glucosidase, −48.2% phosphatase, and −54.5% respiration rate). Microbial biomass C content was also affected by fire at T0 (−32.3%) but was close to its initial value at T5. The results suggest that these soils are particularly sensitive to fire. Adjusting the frequency and intensity of the burns is necessary to minimize their impact on the soil and to ensure the suitability of this management practice. [ABSTRACT FROM AUTHOR]

This study investigated, in a Pinus laricio forest of south Italy, how systematic thinning of different intensities (intense thinning, T45; moderate thinning, T25; clear cut, CC; and no thinning, T0) affected soil biological properties, organic matter trend and carbon (C) storage in soil and plants. Soil carbon content and carbon/nitrogen (C/N) ratio were significantly higher in the T45 than in control, T25 and CC. Under T45, the soils had also the highest enzymatic activities, microbial biomass carbon (MBC) and colonies of fungi and bacteria. The humification parameters (humification ratio, HR; the degree of humification, DH; humification index, HI) indicated T45 as the best silvicultural practice-approach method to manage Pinus laricio forest for increasing soil carbon storage. The dendrometric parameters evidenced that T45 caused the greatest increment in wood growth (diameter and height), showing that the positive effect of the intense systematic thinning (T45) on the mechanical stability of plantation was related to the ability of trees to accumulate large amounts of carbon in their wood tissues. These data were confirmed by wood density value that was the highest in pine trees under the T45. This study showed that in Pinus laricio forest under T45 C stock increased in soil and plant, already 4 years after thinning. [ABSTRACT FROM AUTHOR]

Prescribed burning has been readopted in the last decade in the Central Pyrenees to stop the regression of subalpine grasslands in favour of shrublands, dominated among others by Echinospartum horridum (Vahl) Rothm. Nevertheless, the effect of this practice on soil properties is uncertain. The aim of this work was to analyse the effects of these burnings on topsoil organic matter and biological properties. Soil sampling was carried out in an autumnal prescribed fire in Buisán (NE-Spain, November 2015). Topsoil was sampled at 0–1 cm, 1–2 cm and 2–3 cm depth in triplicate just before (U), ~ 1 h (B0), 6 months (B6) and 12 months (B12) after burning. We analysed soil total organic C (TOC), total nitrogen (TN), microbial biomass C (C mic ), soil respiration (SR) and β-D-glucosidase activity. A maximum temperature of 438 °C was recorded at soil surface while at 1 cm depth only 31 °C were reached. Burning significantly decreased TOC (− 52%), TN (− 44%), C mic (− 57%), SR (− 72%) and β-D-glucosidase (− 66%) at 0–1 cm depth while SR was also reduced (− 45%) at 1–2 cm depth. In B6 and B12, no significant changes in these properties were observed as compared to B0. It can be concluded that the impact of prescribed burning has been significant and sustained over time, although limited to the first two topsoil centimetres. [ABSTRACT FROM AUTHOR]

The main objective of sustainable agriculture is the protection of environment and natural vegetal and soil resources. Accordingly, the objective of this research was to assess the impact of technological systems by minimum tillage on soil biological activity, using the Pedo-Biological Diagnosis of Soil Resources. Our research was conducted on haplic chernozem from Experimental Station of UASVM of Iasi, Romania, during the seasonal dynamic, to the soybean crop, on unfertilized and fertilized agrofond, using moderate mineral doses (N80P80) as average of 2009–2010 period, under minimum tillage (2x disk, paraplow, chisel) compared to conventional (plugging at 20 cm and 30 cm). In the case of soil works with chisel and paraplow without return of furrow, the Pedo-Biological Diagnosis highlights an increase of soil physiological potential, in the both variants (unfertilized and fertilized), unlike the method of alternating the depth of plugging that proved to be ineffective.

BACKGROUND Monoculture is used mostly in conventional agriculture, where a single crop is cultivated on the same land for a period of at least 12 months. In an organic and integrated growing approach, more attention is paid to plant-environment interactions and, as a result, diverse growing systems applying intercropping, catch crops, and green manure are being implemented. Thus, field experiments for evaluation of vegetable/faba bean full intercropping efficiency, in terms of vegetable and faba bean yield and protein content, were set up during two consecutive growing seasons (2014 and 2015). RESULTS Data obtained showed that the most efficient intercropping variants were cabbage/faba bean (cabbage yield 1.27-2.91 kg m−2, immature faba bean pods 0.20-0.43 kg m−2) and carrot/faba bean (carrot yield 1.67-2.28 kg m−2, immature faba bean pods 0.10-0.52 kg m−2), whilst onion and faba bean intercrop is not recommended for vegetable growing since it induces a very low onion yield (0.66-1.09 kg m−2), although the highest immature faba bean pod yield was found in the onion/faba bean intercropping scheme (up to 0.56 kg m−2). CONCLUSION Vegetable/faba bean intercropping can be used in practical horticulture for carrot and cabbage growing in order to ensure sustainable farming and environmentally friendly horticultural production. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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Cover cropping is a widely promoted strategy to enhance soil health in agricultural systems. Despite a substantial body of literature demonstrating links between cover crops and soil biology, an important component of soil health, research evaluating how specific cover crop species influence soil microbial communities remains limited. This study examined the effects of eight fall-sown cover crop species grown singly and in multispecies mixtures on microbial community structure and soil biological activity using phospholipid fatty acid (PLFA) profiles and daily respiration rates, respectively. Fourteen cover crop treatments and a no cover crop control were established in August of 2011 and 2012 on adjacent fields in central Pennsylvania following spring oats (Avena sativa L.). Soil communities were sampled from bulk soil collected to a depth of 20 cm (7.9 in) in fall and spring, approximately two and nine months after cover crop planting and prior to cover crop termination. In both fall and spring, cover crops led to an increase in total PLFA concentration relative to the arable weed community present in control plots (increases of 5.37 nmol g-1 and 10.20 nmol g-1, respectively). While there was a positive correlation between aboveground plant biomass (whether from arable weeds or cover crops) and total PLFA concentration, we also found that individual cover crop species favored particular microbial functional groups. Arbuscular mycorrhizal (AM) fungi were more abundant beneath oat and cereal rye (Secale cereale L.) cover crops. Non-AM fungi were positively associated with hairy vetch (Vicia villosa L.). These cover crop-microbial group associations were present not only in monocultures, but also multispecies cover crop mixtures. Arable weed communities were associated with higher proportions of actinomycetes and Gram-positive bacteria. Soil biological activity varied by treatment and was positively correlated with both the size and composition (fungal:bacterial ratio) of the microbial community. This research establishes a clear link between cover crops, microbial communities, and soil health. We have shown that while cover crops generally promote microbial biomass and activity, there are species-specific cover crop effects on soil microbial community composition that ultimately influence soil biological activity. This discovery paves the way for intentional management of the soil microbiome to enhance soil health through cover crop selection. [ABSTRACT FROM AUTHOR]

The article is devoted to study of the biological activity of soil under sweet corn crops depending on tillage depth, mineral fertilizers application rate with drip irrigation in the soil-ecological conditions of the Dry Steppe Zone of Ukraine. The plan of the experiment foresaw study of such factors: A — tillage depth (moldboard plowing on 20-22 and 28-30 cm); B — mineral fertilizers application rate (no fertilizers, N60P60, N120P120); C — plants density (35, 50, 65, 80 plants ha-1). We used water of the Ingulets irrigation system for irrigation. The water belongs to II quality class by agronomical criteria of the DSTU 2730-94 and its suitability for irrigation is limited. We studied the soil biological activity on variants with 65 plants ha-1 by the indicies of its respiration rate (method of V.I. Shtatnov) and linen decomposition degree (“application” method). At the same time we have made monitoring of the soil meliorative state depending on the moldboard plowing depth by the toxic salts content, anionic-cationic composition of the aqueous soil extract. The results of the laboratory-field experiments prove that the moldboard plowing depth , mineral fertilizers application rates and soil meliorative state have an influence on its biological activity. The maximum respiration rate, which is used to characterize an activity of the aerobic microflora of the upper soil layers, was at moldboard plowing on depth of 20-22 cm at non-fertilized experimental variant — 250.0 mg СО2/m2×hour. Increase of the tillage depth and mineral fertilizers application rate significantly decreased carbonic acid emission to the athmosphere, which was the minimum of 178.3 mg СО2/m2×h. The maximum linen decomposition degree, which is used to characterize an activity of the cellulose-decomposing soil microflora, was at moldboard plowing depth of 28-30 cm at non-fertilized experimental variant — 58.3%. The tillage depth changed cellulose-decomposing soil microflora activity insignificantly. Mineral fertilizers application at the maximum rate of N120P120 decreased cellulose-decomposing soil biota activity 1.7 times comparatively to non-fertilized variant. Higher toxic salts concentration (at 0.006-0.019 %), sodium ions content (at 0.15-0.38 mg-eq/100 g of soil) in the 0-50 cm layer led to decrease of the soil biological activity. We consider, that the best from the agroecological point of view is the variant with moldboard plowing depth of 28-30 cm, mineral fertilizers application rate N120P120. [ABSTRACT FROM AUTHOR]

Prescribed burning is the deliberate application of fire under selected conditions to accomplish predetermined management objectives. It is generally accepted that controlled use of fire has neutral or even positive effects on soils due to its lower temperature, intensity and severity compared to wildfires. However, very few studies have examined the effects of prescribed burning of shrub vegetation in humid mountain areas on soil properties. The objective of this work was to determine the immediate effects of prescribed burning on the quality and biochemical stability of soil organic matter (SOM) in areas encroached by shrubs in the Central Pyrenees (NE Spain). Soil samples were sampled in triplicate immediately before and after burning from the Ah horizon at 0–1, 1–2 and 2–3 cm depths. We quantified the variations as a direct result of burning in (1) the SOM content, (2) the content and mineralization rates of labile and recalcitrant C pools as inferred from incubation assays (141 days), and (3) the soil biological activity related to C cycling (microbial biomass C and β-D-glucosidase activity). Nearly all the soil properties studied were significantly affected by fire, varying in terms of extent of the effect and the soil depth affected. The total soil organic C (SOC), C/N ratio, β-D-glucosidase activity, C-CO 2 efflux and estimated content of labile SOC decreased significantly up to 3 cm depth. The total N and microbial biomass C were significantly affected only in the upper cm of the soil (0–1 cm). These results describe a short-term stronger impact of the prescribed fire on topsoil properties than usually reported. However, comparing these findings to other studies should be performed with caution because of the different environments considered in each case, as well as the differing soil thicknesses found in the literature, typically between 5 and 15 cm, which can lead to a dilution effect associated with the actual impacts of fire on soil properties. In this sense, the choice of a suitable soil thickness or sampling just after burning can be relevant factors in the detection of the immediate effects of fire. Short- and medium-term monitoring of the soils is needed to assess the suitability of this practice for pasture maintenance and for adapting the frequency of prescribed fires in order to minimize its impact on soil. [ABSTRACT FROM AUTHOR]

Discussed topical issues of modern agricultural science in the direction of biological function of agricultural production. Identified priority areas for new and improved farming systems, a system of expanded reproduction of soil fertility and the formation of a balanced eco-system of agricultural production.

Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y biomasa microbiana del suelo, se aplicaron diversas concentraciones de vinaza como enmienda procedente de la industria de alcohol carburante, sobre un suelo afectado por sodicidad con severas limitaciones en las condiciones físicas, químicas y biológicas. Se aplicó un diseño en bloques completos al azar que incluye cuatro tratamientos y tres repeticiones, y muestreos de suelo al inicio y final del proceso a tres profundidades (0-20, 20-40 y 40-60 cm), cuyas variables de respuesta a medir fueron la respiración, C- biomasa microbiana, MO%, pH, CIC, CE, RAS y PSI. La actividad biológica (CO2) y el C-biomasa microbiana mostraron incrementos significativos en el rango ideal para el establecimento del cultivo de caña.To evaluate changes in ESP, SAR and its influence on the activity and soil microbial biomass, different concentrations of vinasse from the fuel ethanol industry as an amendment were applied on a soil affected by sodicity with strong physical, chemical and biological limitations. A randomized complete block design was used involving four treatments and three replications, which included soil sampling at the beginning and the end of the process at three different depths (0-20, 20-40 and 40-60 cm). Variables measured were respiration, microbial biomass C, OM%, pH, CIC, EC, SAR and ESP. Biological activity (CO2) and microbial biomass, C showed a significant increase in the ideal range for planting of sugar cane crop.

The paper analyzes the effect of whole-area site preparation by ploughing and of alternate field and forest crops on the understorey, soil biological activity and physical and chemical characteristics in the commercial forest. Another factor of the study was to assess the effect of the clearcut size on forest stands. Analyzed were 20-years-old stands of pedunculate oak (Quercus robur [L.]) on alluvial sites 1L9 (Fraxino pannonicae-Ulmetum). It can be deduced from the conducted analyses that after twenty years neither different site preparation nor clearcut size affected the understorey and soil biological activity. Field crops and forestry in alternation had a significantly adverse effect on porosity and water-retention capacity in the lower layer of top-soil (25-30 cm). Whole-area ploughing had a negative influence on the loss of organic substances due to accelerated mineralization. Nevertheless, the observed differences are not significant; the values did not fall below critical limits and in no case did they affect other studied site parameters or the development of root systems and aboveground parts of oak trees.

En Chile, el establecimiento de plantaciones comerciales de rápido crecimiento ha sido sostenido en las últimas décadas mediante la sustitución de bosques nativos y conversión de suelos agrícolas. Pinus radiata D. Don es la principal especie productiva, debido a su crecimiento acelerado y adaptabilidad al clima y los suelos. En el presente estudio se plantea que la actividad biológica del suelo es variable a través del año, en respuesta a variaciones de precipitación, temperatura y contenido de humedad de suelo y que el cambio de uso de suelo desde un bosque templado de Nothofagus obliqua (Mirb) Oerst a una plantación con coniferas exóticas, modifica la química del suelo y consecuentemente los procesos de N-min, C-min y la actividad biológica del suelo. Esta hipótesis fue examinada en un bosque de N. obliqua y una plantación de P. radiata del centro-sur de Chile (40°07' S, 72° O). Se evaluó mensualmente la tasa mineralización de nitrógeno (N-min), cabono (C-min) y la actividad enzimática potencial del suelo (ureasa, proteasa e hidrólisis de la fluoresceína diacetato) entre septiembre 2003 y mayo 2005. Los resultados demuestran que los niveles de las variables de actividad biológica del suelo fueron significativamente diferentes entre las parcelas de bosque y plantación (Lambda de Wilk = 0,022; F 5,80 = 733; P < 0,0001) y entre los meses (Lambda de Wilk = 2,01E-6; F 100 ,395 = 84; P < 0,0001), siendo la actividad biológica mayor en el suelo de bosque de N. obliqua que en la plantación de P. radiata. Las tasas de N-min y C-min presentaron un comportamiento estacional, con los mayores montos en los meses de primavera-verano. Sin embargo, las actividades enzimáticas no mostraron una clara variación estacional. Los mayores valores de mineralización y actividad enzimática en el bosque de N. obliqua, se deberían a la composición y características químicas de la hojarasca. Producto del cambio de uso de suelo y manejo silvícola, la plantación de P. radiata cambia la química y la relación C/N del suelo con una menor tasa de descomposición de la materia orgánica, y como consecuencia, los procesos de mineralización (C, N), la actividad biológica y retorno de nutrientes al suelo se reducen en comparación con el bosque de N. obliqua.In Chile, commercial forests plantations have increased during the last decades due in part to replacement of native forests and conversion of agricultural soils. Pinus radiata D. Don has been the main tree planted, due to its rapid growth and adaptability. In the present study we proposed that biological activity varies along the year due to changes of precipitation, temperature and soil water content and mainly because the conversion of native forest to exotic P. radiata plantations alters the soil chemistry, N and C mineralization and the potential enzymatic activity in these soils. This hypothesis was examined in a Nothofagus obliqua (Mirb) Oerst forest and P. radiata plantation in central-southern Chile (40°07' S, 72° W). In this study, the rate of nitrogen mineralization (N-min), carbon mineralization (C-min) and the potential enzymatic activity of soils (urease, protease and fluorecein diacetate hydrolysis) were determined between September 2003 and May 2005. Results showed that soil biological activity was significantly different between forest and plantations (Wilk's Lambda = 0.022; F> 5,80 = 733, P < 0,0001), and among the months (Wilk's Lambda = 0.01 E-6, F100,395 = 84, P < 0,0001), with vaiues for N. obliqua forest significantly higher (Tukey < 0.01) than those for P. radiata plantation. N-min and C-min rates showed seasonal variability with the higher values in spring and summer months. For enzymatic activity there was not a clear seasonal variation. The higher values of C and N-min and enzymatic activity in the N. obliqua forest could be explained by differences in composition and chemistry of litter. Consequently, P. radiata plantation changed soil chemistry and C/N ratio resulting in lower decomposition rates of organic matter and in consequence, reduced mineralization of C and N and soil biological activity compared to the original soil of N. obliqua forest.

A field experiment was conducted to study the effect of nutrient management practices on the performance of soybean - safflower sequence in Vertisols. The safflower equivalent yield (2418 kg/ha-1; gross returns (Rs. 53196/ha-1); net returns (Rs 33734/ha-1) and B:C ratio (2.8) were significantly superior either with the application of NPK to the system + 5 t FYM/ ha to safflower; or NPK to the system + soybean residues to safflower; or NPK to the system + both crop residues. Similar trend was also observed with respect to soil health indicators viz., soil respiration (108 μg C/g soil/10 days), microbial biomass C (284 μg C/g soil), microbial biomass N (41.9 μg N/g soil), mineral N (13.8 μg N/g soil) and net N mineralization (5.4 μg N/g soil/ 10 days). Significant improvement was observed in terms of PGPR and Trichoderma sp were found when NPK + crop residues were applied to the system. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of elevated CO (700 ± 23 μmol mol) on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated CO was associated with decreased quantities of reducing sugars, starch, and soluble amino acids, and with increased quantities of soluble sugars, total sugars, and soluble proteins in wheat seedlings under Cd stress. The contents of total soluble sugars, total free amino acids, total soluble phenolic acids, and total organic acids in the rhizosphere soil under Cd stress were improved by elevated CO. Compared to Cd stress alone, the activity of amylase, phenol oxidase, urease, l-asparaginase, β-glucosidase, neutral phosphatase, and fluorescein diacetate increased under elevated CO in combination with Cd stress; only cellulase activity decreased. Bacterial abundance in rhizosphere soil was stimulated by elevated CO at low Cd concentrations (1.31-5.31 mg Cd kg dry soil). Actinomycetes, total microbial abundance, and fungi decreased under the combined conditions at 5.31-10.31 mg Cd kg dry soil. In conclusion, increased production of soluble sugars, total sugars, and proteins in wheat seedlings under elevated CO + Cd stress led to greater quantities of organic compounds in the rhizosphere soil relative to seedlings grown under Cd stress only. Elevated CO concentrations could moderate the effects of heavy metal pollution on enzyme activity and microorganism abundance in rhizosphere soils, thus improving soil fertility and the microecological rhizosphere environment of wheat under Cd stress. [ABSTRACT FROM AUTHOR]

The soils of the studied area function in different temperature regimes: under the influence of permafrost (Turbic Histic Cryosol and Cryic Eutric Histosol) and long-term seasonal freezing (Albic Podsol). Sporadic permafrost defines the differences in temperature regimes. All soils are characterized by the low production of carbon dioxide (an average of 160 mg CO/(m h)), indicating their low biological activity. The lack of easily available carbon for microorganisms is detected in all investigated soils by the C: C ratio despite the high reserves of organic matter. The value of CO emission and the C: C ratio are 'site-specific' for the region of investigation and may be used as indicators of environmental changes. Cryogenic peat soils represent a unique natural object and ensure the functional diversity and integrity of northern taiga ecosystems in Western Siberia. [ABSTRACT FROM AUTHOR]

During the years 1998-2000 soil chemical (Corg, Nt, pH), textural (sand, silt clay) and microbiological (microbial biomass carbon - CMB, microbial extracellular carbon - CEX, respiration, ammonification, nitrification) characteristics were tested on grassed chernozem [mollisol] after arable land setting-aside. Different harvest management was also tested: black and green fallow, one or two mulching per year, three cuts with plant biomass removal. For the evaluation of the influence of management and plants we have used three main criteria: (1) µg CMB/g dry soil, (2) ratio CMB/Corg (%), (3) µg CEX/mg CMB or eight criteria respectively: (4) ratio of measured and model values of CMB, (5) ratio of measured and model values of CEX/CMB, (6) potential respiration with glucose, (7) potential ammonification with peptone and (8) potential nitrification with (NH4)2SO4. According to these criteria, the best harvest management after arable land setting-aside from 5 different systems, which were tested, could be based on one or two mulching per year. It could be stressed that the two mulching was evaluated as the best in sum of dry mass yield (27.5 for mixtures, 20.1 for legumes and 14.2 for grasses - in t/ha/3 years). The use of legumes (Trifolium repens L. - Medicago lupulina L. - Lotus corniculatus L. - Medicago media Pers.) or grasses [Bromus catharticus Vahl - Arrhenatherum elatius (L.) Presl - Festuca pratensis Huds - Dactylis aschersoniana Graebn.] as cover plants was more successful than the use of their mixtures.

Sustainability in agriculture means the inclusion of several aspects, as sustainable agriculture systems must not compromise not only their ability to satisfy future needs by undermining soil fertility and the natural resource base but also sustainable agriculture has had to address a range of other issues including energy use, efficient use, and recycling of nutrients, the effects on adjacent ecosystems including the effects on water bodies and climate change. Organic manures are an important factor to keep the soil fertility level of soils. However, their management is often related to large emissions. In this context, anaerobic digestion is-similarly to composting-a treatment option for stabilization of biogenic wastes leading to a residual product called digestates, enabling the sanitation and the recycling and use as fertilizer. It is also a means to obtain energy from wastes as well as from dedicated energy crops. Therefore, anaerobic digestion potentially addresses several aspects of agricultural sustainability. This review discusses the current state of knowledge on the effects of anaerobic digestion on organic compounds in digestates and the most important processes influencing N emissions in the field, as well as the possible long-term effects on soil microbial biomass and soil fertility. The main findings are that (1) the direct effects of anaerobic digestion on long-term sustainability in terms of soil fertility and environmental impact at the field level are of minor relevance. (2) The most relevant effects of anaerobic digestion on soil fertility as well as on N emissions will be expected from indirect effects related to cropping system changes such as changes in crop rotation, crop acreage, cover cropping, and total amounts of organic manures including digestates. Furthermore, (3) the remaining organic fraction after anaerobic digestion is much more recalcitrant than the input feedstocks leading to a stabilization of the organic matter and a lower organic matter degradation rate after field application, enabling a similar reproduction of the soil organic matter as obtained by direct application of the feedstock or by composting of the feedstock. (4) Regarding emissions, the main direct effect of anaerobic digestion on a farm level is the influence on gaseous emissions during manure or digestate treatment and handling, whereas the direct effects of anaerobic digestion on a field level on emissions (NH and NO emissions, NO leaching) are negligible or at least ambiguous. (5) The main direct effects of anaerobic digestion on the field level are short-term effects on soil microbial activity and changes in the soil microbial community. Therefore, in terms of the effects on agricultural sustainability, potential cropping system-based changes induced by introduction of biogas plants are probably much more relevant for the overall performance and sustainability of the cropping system than the direct effects triggered by application of digestates in comparison to the undigested feedstocks. Furthermore, to get the full potential advances from implementation of biogas plants in terms of improvement of the nutrient use efficiency and reduction of greenhouse gas emissions, there is the need to introduce more sophisticated techniques to avoid counteracting effects by pollution swapping, e.g., by gas-tight closure of the digestate stores and direct soil incorporation of the field-applied digestates. [ABSTRACT FROM AUTHOR]

Feeding the world’s population in 40 years will require improved efficiency in the use of plant nutrients and enhancement of soil resources. Over the past 60 years, agricultural production has rapidly increased; however, continued degradation of soil may limit further increases. Improving the soil through enhanced soil biological activity has been proposed as a method of increasing the capacity of the soil to produce crops. Ongoing evaluations of one soil biological fertilizer with a patented process to convert and complex manure into stable finished products (AgroBiotic fertilizers) have been conducted in research plots and producer fields and have shown positive effects on grain yield and potato production. These effects are larger in soils with limited biological activity, suggesting that adding this unique AgroBiotic fertilizer helps restore the biological nutrient cycling in the soil. New developments and innovations that improve nutrient availability and the efficacy of soil biological fertilizers have the potential to help restore degraded soils and improve their production efficiency and capacity to feed the world’s population. [ABSTRACT FROM AUTHOR]

Soil degradation is a major threat to Southern Africa's agricultural production. Crops show generally weak responses to mineral fertilizers on degraded soils. A three-year study was conducted between 2009 and 2012 on smallholder farms in eastern Zimbabwe to explore entry points for rehabilitating degraded croplands using principles of integrated soil fertility management (ISFM) supported through farmers' local knowledge of soils. Participatory research approaches were first used to investigate farmers' understanding of soil degradation and the commonly used local diagnostic indicators. Farmers' determinants of degraded soils centered on crop performance, indicator weed species and soil physical attributes, and matched laboratory parameters. Overall, physical and chemical properties of the degraded soils were significantly lower than reported values for productive sandy soils in Zimbabwe. Evaluated on ten degraded field sites of corresponding catenary positions and similar slope, the main ISFM options involved nitrogen-fixing herbaceous legumes planted in the first year, with subsequent addition of cattle manure in the second year. In the third year, the influence of the ISFM options on maize productivity and changes in soil biological activity were then evaluated. Phosphorus was applied every year under each sequence. The controls were natural fallow and continuous maize. The treatments were randomly assigned to plots at each of the experimental sites and replicated across farms. Above-ground biomass carbon (C) and nitrogen (N) accumulation was 3038 kg ha − 1 and 203 kg ha − 1 , respectively, under 1-year indigenous legume fallow (indifallow) against 518 kg C ha − 1 and 14 kg N ha − 1 under 1-year natural fallow. Two-year indifallow produced approximately three times the biomass N attained under the 2-year natural fallow. When all the treatments were planted to a maize test crop in the third year, herbaceous legume-based sequences showed the highest response to mineral fertilizer N compared with natural fallow-based sequences and continuous fertilized maize. A regression of maize yields against mineral N fertilizer showed a maximum yield of 2.5 t ha − 1 under the herbaceous legume-based sequences against 1 t ha − 1 under continuous fertilized maize and natural fallow-based options following addition of 120 kg ha − 1 of mineral N fertilizer. ‘Green-start’, a Crotalaria juncea L. (sunnhemp)-based sequence, and ‘Indifallow-start 1’, an indigenous legume-based sequence, gave the highest microbial biomass C (MBC) of 243 mg kg − 1 soil compared with 187 mg kg − 1 soil under continuous maize. Microbial biomass N showed a similar trend. Under ‘Green-start’ and ‘Indifallow-start 1’, MBC to organic C ratio averaged 7; about one and half times more than under natural fallow-based sequences and continuous fertilized maize. Consistent with microbial biomass, soil carbon dioxide (CO 2 ) emission under ‘Green-start’ and ‘Indifallow-start 1’ was 22% higher than under natural fallow-based sequences. Continuous maize treatments gave higher metabolic quotients ( q CO 2 ) than legume-based sequences, indicating a lower microbial efficiency under the former. We concluded that short-term restoration of productivity of degraded sandy soils should focus on high quality organic resource application and P fertilization to stimulate microbial activity and induce responses to mineral fertilizers. When coupled to P fertilization, herbaceous legume-based ISFM sequences provide a potential entry point for reversing soil degradation and offer opportunities for increasing crop productivity in dominant smallholder farming systems of Zimbabwe and other parts of Southern Africa. [ABSTRACT FROM AUTHOR]

The study focused on the change of microbial characteristics affected by Plumbum pollution with purple paddy soil in an incubation experiment. The results showed that low concentration of Plumbum had little effect on most of microbial amounts, biological activity and enzymatic activity. However, denitrifying activity was inhibited severely, and inhibition rate was up to 98%. Medium and high concentration of Plumbum significantly reduced the amounts and activity of all microorganisms and enzymatic activity, which increased with incubation time. Negative correlations were found between Plumbum concentrations and microbial amounts, biological activity and enzymatic activities except fungi and actinomyces. Thus they can be used to indicate the Plumbum pollution levels to some extent. LD50 of denitrifying bacteria (DB) and ED50 of denitrifying activity were 852mg/kg and 33.5mg/kg. Across all test soil microbes, denitrifying bacteria was most sensitive to Plumbum pollution in purple paddy soil. Value of early warning showed that anaerobic cellulose-decomposing bacteria (ACDB) and actinomyces were also sensitive to Plumbum pollution. We concluded that denitrifying activity, actinomyces, ACDB or DB can be chosen as predictor of Plumbum contamination in purple paddy soil. [ABSTRACT FROM AUTHOR]

Impact of Cr3+ pollution on soil microbial quantity, enzyme activity and biological activity in purple paddy soil were studied under incubation conditions. The results showed that amounts of all tested microbes and enzyme activities in soil were inhibited by low Cr3+ concentration (200mg/kg). After 7-day incubation, sulfate-reducing activity, methanogen activity, denitrifying activity and anaerobic nitrogen-fixing activity in soil were reduced by 34%, 66%, 98% and 65% respectively. Amounts of soil microbes were remarkably inhibited with medium Cr3+ concentration (400mg/kg), all with reduction of more than 50%; and all tested soil biological activity was almost recovered in the fourth week except soil denitrifying activity. Activities of urease, invertase, neutral phosphatase and catalase were decreased by 60%, 21%, 59% and 42%, respectively. With high Cr3+ concentration (1600mg/kg), amounts and activities of tested microbes had only about 1% of that with control. As calculated from the regression equation, the ED50 (ecological dose) values of activities of soil urease, invertase and catalase were around 800mg/kg; the ED50 values of soil sulfate-reducing activity, methanogen activity and anaerobic nitrogen-fixing activity were also around 800mg/kg with an exception of soil denitrifying activity which ranged 35 to 39 mg/kg. According to the Standards of National Soil Environmental Quality in China and their sensitivities to 400mg/kg Cr3+ concentration, quantity of denitrifying bacteria, urease activity and denitrifying activity could be selected as indicators of early warning for Cr3+ pollution in purple paddy soil. [ABSTRACT FROM AUTHOR]

Results are presented that have been obtained in studies on the effect of forests growing in the steppe zone on the conditions of formation and qualitative and quantitative composition of organic matter and on the properties of humus in chernozem soils of neighboring biogeocenoses. [ABSTRACT FROM AUTHOR]

The most important indicators of biological activity (respiration, methane genesis, nitrogen fixation, denitrification, and size and structure of the microbial population) were determined in coprolites of two types of earthworms ( Lumbricus rubellus considered as the 'litter' type and Aporrectodea rosea as the 'soil' type) in the model experiment, in which the earthworms were kept separately and together, as in soddy-podzolic loamy soil. The biological activity of coprolites was significantly higher than in the soil and varied between worm species. [ABSTRACT FROM AUTHOR]

Abstract: A study was conducted in the greenhouse to determine the effects of conventional and organic nitrogen (N) fertilizer on Fusarium wilt, caused by Fusarium solani, in northern highbush blueberry (Vaccinium corymbosum L. ‘Legacy’). Root colonization by mycorrhizal fungi, soil microbial activity, and leaf antioxidants content was also measured the treatments. Plants grown with organic N fertilizer exhibited a lower incidence of Fusarium wilt than those grown with conventional N fertilizer (5% and 30% by the end of the experiment, respectively). Organic fertilizer also increased the soil biota activity, mycorrhizal colonization, and leaf antioxidant content relative to conventional N source. The results suggest that organic N fertilizer may improve the tolerance of blueberry to soil pathogens, such as F. solani. [Copyright &y& Elsevier]

Climate change has an impact on agricultural production, including the greater persistence of plant pathogens in the environment. Therefore, the question arises as to how to effectively and safely protect plants by using chemicals, the number of which is decreasing each year. The aim of this study was to evaluate the fungistatic effect of 2 acetylthiophenethiosemicarbazone (2actpTS) and Cis-jasmonethiosemicarbazone (JTS) against Fusarium culmorum (Fc) on winter wheat seedlings. The influence of thiosemicarbazones (TSs) on the health status and phytotoxicity of seedlings and soil biological activity was investigated. Before TSs application (watering or spraying), soil was infected with F. culmorum (strain No. 37). The substance type and method of its application significantly influenced only the fresh weight of the seedlings. The varying phytotoxicity of the molecules depended primarily on their application method to the plants. The highest seedling phytotoxicity was recorded when compounds were applied during watering and the lowest when they were sprayed. The results showed that the application of substances 2actpTS and JTS, both in the form of watering and spraying, had a positive effect on plant health status, as expressed by the disease index (DI) value. The presence of the infectious agent and the type of chemical compound increased soil enzyme activity. The highest total number of bacteria was found in the soil that was infected with Fc and in soil samples where JTS was applied by watering and spraying. The highest utilization of amines, amides and amino acids by microorganisms was found in the samples where JTS was applied. The obtained results will be used to create intermediate products for the protection of cereals against Fusarium diseases, not only at the stage of germination and tillage of plants, but also at subsequent developmental stages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rhizosphere of sugarcane and Urochloa spp. accelerated weathering of Technosols. • Dissolution of primary minerals triggered illite–smectite transformations. • The rhizosphere is the key driver for soil functionality in the studied Technosols. The rhizosphere is a highly biogeochemically active site influencing several soil processes that are crucial for soil formation (e.g., mineral weathering). We studied weathering processes in embryonic Technosols constructed with limestone mine spoils, cultivated with sugarcane for two and six years (illitic siltstone areas: SC2 and SC6) and forage grasses (mainly Urochloa spp.) for 20 years (smectitic black shale area: P20). Rhizosphere and bulk soils were characterized through biological, chemical, and mineralogical analyses. We found contrasting biogeochemical environments when comparing rhizosphere and bulk soils. The pH values were about 1 unit lower, dissolved organic carbon concentrations were up to 3 times higher, and the average enzymatic activity was about 3 times higher in the rhizosphere soils compared to the bulk soils of the studied Technosols. A higher biological activity in the rhizosphere triggered the weathering of primary minerals (dolomite, feldspar, muscovite, quartz), causing the release of K, Ca, Mg, and Si from the mineral structure into the soil solution. The enrichment of the rhizospheric soil solution with Si and bases (mainly Ca and Mg) triggered the transformation of clay minerals and led to the formation of amorphous Si phases. Under sugarcane, smectite content increased from 18% in the siltstone to 44% in the SC6 rhizosphere. Under forage grasses, there was an increase in smectite contents from 58% in the black shale to 75% in both the rhizosphere and bulk soils. The main clay transformation process was a topotactic transformation from illite to smectite through progressive interstratification, supplied by the high availability of Si, Ca, and Mg in the rhizosphere. Our results highlight the pivotal role of rhizospheric processes in mineral weathering of Technosols developed from limestone mine waste. These processes may accelerate pedogenesis, and, consequently, the recovering of the soil functions essential for mine reclamation processes. [ABSTRACT FROM AUTHOR]

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A bare ground control was compared with four mulch types (anaerobically and aerobically fermented marc (grape pressings), inter-row grass clippings and shredded office paper) which were applied in winter under 10-year-old Riesling vines in a 10-replicate randomized block design in New Zealand, over 2 consecutive years. Functional soil biological activity, as measured by Biolog Ecoplates and bait lamina probes, was increased 2–4 times in the two marc and paper treatments, compared with the control, an effect relating to the elevated soil moisture and reduced temperature fluctuations under these mulches. Nutrient levels and the C:N ratio were also affected in these treatments. The mulched paper lowered vine canopy density by up to 1.4 times that of the other treatments, an effect which probably led to elevated light penetration into the canopy and consequently increased canopy temperature and photosynthesis and lowered canopy humidity. These changes to soil and vine characteristics increased grape skin strength by up to 10% in the paper treatment and sugar concentrations by 1.2–1.4°Brix in the two marc and paper treatments. The severity of Botrytis cinerea infections in the anaerobic marc, aerobic marc and paper treatments were reduced to 12, 3 and 2.2% of the control, respectively, in field assessments averaged over two consecutive harvests. [Copyright &y& Elsevier]

Botrytis bunch rot is a disease that causes loss of yield and quality in many fruit and vegetable crops in temperate climates worldwide. The rot is caused by the fungus Botrytis cinerea, a saprophytic necrotroph. In grapes, the presence of the fungus can reduce yield, taint wine and increase its sensitivity to oxidation. In the current work, inter-row phacelia and ryegrass were mulched in situ in winter 2005 and compared with a bare ground control. The mulches were applied under 10-year-old Chardonnay vines in a 10-replicate randomized block design in New Zealand. Functional soil biological activity increased by 1.5-4.5 times in the two cover crop treatments compared with the control, an effect related to elevated soil moisture in these treatments. This increase in soil moisture and a higher rate of soil biological activity increased vine debris degradation, reduced B. cinerea primary inoculum on the debris and decreased B. cinerea severity at flowering (December 2005) and harvest (April 2006). These results show the potential of mulched cover crops to enhance soil ecosystem services, reduce variable costs and improve the sustainability of viticulture and potentially other agricultural systems, in temperate climates worldwide. [ABSTRACT FROM AUTHOR]

Abstract: The soil fauna plays an important role in regulating nutrient cycling through predation and comminution of organic residues. The bait-lamina test was proposed as a practical mean to assess soil faunal feeding activity. The test consists of vertically inserting 16-hole-bearing plastic strips filled with a plant material preparation into the soil. We assessed the value of the bait-lamina test in the mixed grassland ecoregion of Canada, using 5-year-old seeded grass field plots. There were five treatments of grass communities, i.e. monocultures of (1) Russian wild rye, (2) switchgrass, (3) green needlegrass, or (4) western wheatgrass, and (5) a grass mixture of western wheatgrass+green needlegrass+switchgrass+little blue stem, which were distributed in four complete blocks, and six bait mix treatments, i.e. bait made with ground tissue of (1) Russian wild rye, (2) switchgrass, (3) green needlegrass, (4) western wheatgrass, (5) alfalfa, or with (6) wheat bran, which were randomized in each plot. Bait-lamina strips were used in groups of five strips inserted in the soil; they were equally spaced across the inter-row. The analysis revealed a marginally significant effect (P =0.065) of plant community on soil faunal feeding activity with more activity in mixed grass species compared to green needlegrass plots. Bait flavour had no significant effect (P =0.22) on feeding. More (P <0.0005) feeding activity was detected close to the soil surface (0–5mm deep) than at 20mm below the surface and at deeper depths. Feeding activity was relatively low over the 65-day period of the test (13 June to 17 August 2005), with 8.3% and 2.0% of the lamina (holes filled) showing signs of feeding in the 0–5 and 5–15mm soil layer. We conclude that the bait-lamina test is appropriate to assess the activity of surface litter processing fauna in mixed grassland, but it is not a good indicator of the decomposition occurring in the soil matrix, where most litter is produced. We recommend the use of a large number of replicated bait-lamina strips and a whole growing season incubation period in soils of the semiarid prairie ecoregion where the surface litter layer is thin and faunal saprobes are relatively scarce. [Copyright &y& Elsevier]